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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c2d4ba283ee59a6c6a8b92a39dc48a8f067d318f442f8ccdf461ed84e64c069' 
  AND token = 'Owv+Reg4QywfHNZO3EEWz2P2ZDrtyAnAtETB3ar7MNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}